1. Field of the Invention
The present invention relates to an automatic transmission for a FF(Front Engine, Front Drive) vehicle, and, in particular, to an oil reservoir device for an automatic transmission.
2. Description of the Prior Art
Conventionally, in an automatic transmission, a valve body is positioned on a lower section of a transaxle casing, and an oil pan is positioned to cover the valve body. Oil accumulates in the oil pan which serves as an oil reservoir device.
However, in a FF vehicle, a subframe runs through the lower section of the transaxle casing for the automatic transmission, specifically, on section where the valve body and the oil pan are located. For this reason the valve body is positioned close to an upper section specifically, close to a rotational axis of the automatic transmission, to avoid obstruction by the subframe.
As a result, this space available for the oil reservoir is small. At high temperature, oil level becomes elevated, and when this level reaches the rotating member, oil starts to blow out through an oil breather plug as a result of agitation of the oil. On the other hand, if an amount of oil is reduced to prevent agitation, oil level becomes too low at reduced temperature and air-intake is produced at a pump suction. This has a detrimental effect on running performance of the vehicle.